1. Field of the Invention
This invention relates to high precision timing signal generators and more particularly to a timing signal generator which can meet the stringent requirements for a video composite sync signal for commercial television by providing a complex, high resolution signal over a frame period which is extremely long compared to the resolution of the signal.
2. Background of the Invention
The video component of a standard NTSC or PAL television signal contains precisely specified timing information called composite sync in addition to the actual video information. This composite sync signal controls such features as horizontal and vertical synchronization, horizontal and vertical retrace, and intensity level. Well established standards place stringent demands on the composite sync signal. It must provide precise, periodic timing relationships while complying with extremely close frequency tolerances. This places similar constraints on many signals related to composite SYNC. While it has long been known to provide inexpensive timers such as counters responsive to clock signals for many purposes, the demands of various standardized composite sync and related video signals have been too stringent and disparate to permit the use of these simple timing mechanisms to generate the composite sync signal. Consequently, it has been necessary to sacrifice flexibility and multiple output capability when utilizing analog based circuitry such as crystal controlled oscillators to meet the tolerance and high frequency requirements of the signals.